1. Technical Field
This invention generally relates to monitoring devices that monitor engineering conditions of pneumatic tires and, more particularly, to an apparatus and method for connecting the power supply to an electronic monitoring device mounted in a pneumatic tire. Specifically, the present invention relates to an apparatus and method for supplying power to the components of an active monitoring device after the components are mounted or cured into a pneumatic tire or mounted or cured into a patch that is then connected to a pneumatic tire.
2. Background Information
Monitoring engineering conditions of pneumatic tires is becoming increasingly desired by tire consumers who use expensive tires or who place large amounts of miles on the tires. The monitoring is preferably performed while the tires are in use on the vehicle without requiring the tires to be removed, the vehicle slowed, the tires specially positioned, or having a person position a reader in a special position to take the measurement.
Numerous types of monitoring devices are known in the art for performing these measurements. For instance, the monitoring device may include a pressure sensor and a temperature sensor connected to a controller having various timers, storage devices, and transmitters/receivers. The data created by the pressure sensor or temperature sensor may be stored in the storage device and later transmitted out of the tire with an antenna by the transmitter. Other types of monitoring devices may be positioned primarily outside the tire and connected to a pressure or temperature sensor through the tire's valve stem. Still other types of monitoring devices use a passive circuit embedded within the tire that is energized by inductive magnetic coupling. Further examples of monitoring devices are disclosed in U.S. Pat. Nos. 5,573,610, 5,573,611, and 5,562,787.
Active, self-powered monitoring devices use an antenna to transmit data from the monitoring device to a data gathering device positioned outside of the tire. One of the problems in the art is to position the antenna in the tire such that data are accurately and reliably transmitted to the data gathering device. Positioning the antenna close to the outside of the tire minimizes the amount of material through which the transmissions must pass before exiting the tire. One of the more desirable antenna positions is thus to have the antenna embedded within the tire sidewall or within a patch directly connected to the tire sidewall. The bead ring and apex filler tend to interfere with transmissions and a desirable antenna position locates the antenna above these items. Unfortunately, the areas of the tire adjacent the bead ring and the apex filler are low flex areas which are desirable mounting positions for the other components of the monitoring device. The art thus desires an invention that accommodates both positions.
One method of anchoring the components of the monitoring device within a pneumatic tire is to cure the monitoring device within the body of the tire. The components may also be cured within a patch that is connected to the innerliner. A significant problem with curing these elements in the body of a tire or the body of a patch is that the battery or power source used to supply power to the monitoring device is easily damaged or destroyed by the heat of the curing process. The risk of damage to the battery has prevented self-powered electronic monitoring devices from being embedded within a green tire and then cured into the tire during the green tire cure process. The damage to the battery is especially unfortunate because positioning the antenna and the monitoring device components within the tire body or within the body of a patch allows the components and antenna to be ideally positioned and secured for use within the tire. The art thus desires an apparatus and method for connecting the monitoring device to the tire by curing the components of the monitoring device within the body of the tire or the body of a patch and then subsequently connecting the battery to the components.